Autonomic refresh of a materialized query table in a computer database
AssigneeInternational Business Machines Corporation
InventorJohn Matthew Santosuosso
Life of this patent
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Abstract
A method autonomically refreshes a materialized query table (MQT) in a computer database to improve database performance and utility. In preferred embodiments, the query optimizer autonomically initiates a refresh of MQT depending on an estimated time for the query to access the base tables. In other preferred embodiments, the query optimizer estimates the time for the query to access the base tables and compares it to the estimated time to refresh the MQT to determine whether to refresh the MQT and run the query over the MQT rather than the base tables.
Claims3
A method for a refreshing a materialized query table (MQT) in a database, the method comprising the steps of:
- parsing a query to identify a database table with a MQT in deferred maintenance;
- determining whether to update the MQT in deferred maintenance to execute the query by performing the steps of:
- estimating a time to execute the query over a base table corresponding to the MQT in deferred maintenance;
- estimating a time to update the MQT in deferred maintenance;
- comparing the estimated time to update the MQT in deferred maintenance and the estimated time to execute the query over the base tables;
- updating the MQT in deferred maintenance where the estimated time to update the MQT is less than the time to execute the query;
- and
- executing the query over the now updated MQT in deferred maintenance.
Dependencies are inferred from the claim text.